Solvated and Deformed Hairy Metal–Organic Polyhedron

Abstract

Despite the fact that numerous studies have been conducted to explore the crystalline structures of various metal−organic polyhedrons (MOPs), the direct probing of solvated and deformed structures of MOPs is still rare but critical to the development of processing protocols and the understanding of their structure−property relationship for gas separation and ion transportation. Here, MOPs from the coordination of isophthalic acids and Cu 2+ are covalently functionalized with alkyl chains for studies in solutions and at the air/water interface, respectively. As suggested from small-angle scattering studies, the MOP structures in the solvated state remain intact while the grafted linear alkyl arms exhibit an extended conformation, allowing solvent molecules to penetrate into the cavity of MOPs. Meanwhile, under surface pressure at the water/air interface, the hairy MOP structures, as suggested by in situ neutron reflectivity studies, can be deformed and MOP cores are close together while the grafted chains are squeezed upward and downward toward liquid and air phases, respectively. This discovery provides the first direct evidence for the existence of an ion transportation active conformation of hairy MOPs.

Unique Dynamics of Hierarchical Constrained Macromolecular Ligands on Coordination Nanocage Surface Promotes Facile and Precise Assembly of Polymers

“…Consistent with the theory, no obvious lag phase period can be observed in the reaction kinetics of C 7 -CNC-SP because the small-size native ML (C 7 -IPA) cannot pack tightly on the CNC surface, allowing free diffusion of MLs at the initial reaction stage. 13 After the lag phase period, the ML substitution reaction kinetics consistently follows a logarithmic time dependence, implying strongly coupled and hierarchically constrained ML dynamics within CNC-SP induced by multiple coordination bonds and space confinement resulting from high graft density of polymers on the CNC surface. 48−50 The overall ML substitution kinetics on CNCs is distinct from that of coordination macrocycles (simple first-order reaction) by showing complex reaction mechanism resulting from the strong cooperative dynamics among all the MLs in one CNC cluster via the correlated coordination bond forming/breaking among the MLs and constrained ML diffusion by the crowded surface ML layers.…”

“…Their complementary applications enable the complete structural studies of inorganic−organic hybrid nanomaterials, PNC of CNCs. 11,13,38,42 In this work (Scheme 1), SAXS and SANS combined with SEC are used to monitor the solutions of CNC nanocomposites, and direct evidence with quantified kinetics for macromolecule-substitution of CNC by extra free macromolecular ligands and macromolecule-exchanging among CNC nanocomposites in their mixture solutions is provided. The unique solutions dynamics of CNC nanocomposites is further applied to direct the rational design of CNC nanocomposites with hybrid macromolecular layers and organo-gels or polymer network vitrimers with desired high mechanical strength at typical service environment and promising processability at high temperature.…”

Model2SAS: software for small-angle scattering data calculation from custom shapes

“…In particular, nanoparticles (NPs) or supramolecular assemblies with various morphologies can be accurately determined and their dynamic structural evolution can be monitored, facilitating the exploration of their formation and self-assembly mechanisms (Nyman, 2017;Yin et al, 2016;Sun et al, 2017). As a good complement for SAXS, small-angle neutron scattering (SANS) demonstrates unique advantages in the study of magnetic and organic materials because neutrons have a magnetic moment and high sensitivity to hydrogen and its isotopes (Lindner & Zemb, 2002;Feigin & Svergun, 1987;Li et al, 2020). Among the abundant structural information provided by SAS, that derived from solution SAS is a unique subset which can give the in situ shape and an internal structure description of particles in solution (Nyman, 2017;Mertens & Svergun, 2010).…”

Modulating Polymer Dynamics via Supramolecular Interaction with Ultrasmall Nanocages for Recyclable Gas Separation Membranes with Intrinsic Microporosity

“…The CNCs have an internal cavity of 1.9 nm that is accessible from eight triangular apertures of 0.8 nm and six square apertures of 1.2 nm. 48,49 BET analysis on the CNC/P4VP nanocomposites, a pure CNC crystalline sample, and a pure P4VP sample has been carried out. The nanocomposites of CNC/P4VP show reversible Type I isotherms for microporous materials (Figure 4a), which is similar to the pure CNC crystalline sample (Figure S8a).…”

“…Suggested from the above dynamic studies, the rigidness of P4VP chains is strengthened upon their complexation with CNCs, and thus, the frustrated packing of P4VP is achieved, allowing the fast transportation of gas molecules. The CNCs have an internal cavity of 1.9 nm that is accessible from eight triangular apertures of 0.8 nm and six square apertures of 1.2 nm. , BET analysis on the CNC/P4VP nanocomposites, a pure CNC crystalline sample, and a pure P4VP sample has been carried out. The nanocomposites of CNC/P4VP show reversible Type I isotherms for microporous materials (Figure a), which is similar to the pure CNC crystalline sample (Figure S8a).…”